Chapter 7 - Occurrence of microplastics and nanoplastics in marine environment

Abstract

The plastic materials are converted into microplastics (MPs) and nanoplastics (NPs) by oxidation, hydrolysis, mechanical corrosion, photodegradation, and biodegradation. The actual sources of MPs and NPs are difficult to trace because of their small size, degradation nature, and fragmentation of the debris. The MPs sources in the marine environment are from land and include industrial waste, runoff, beach visitors, and wastewater from research stations. Ecocline is the process of MPs transportation from terrestrial sources to the seas and oceans through rivers and estuaries. The fibers and fragments type MPs are found around 80% in the ocean and constitute more than the granules and pellets. MPs and NPs concentrations are higher in coastal sediments when compared with the sea surface and water column. MPs and plastic materials are consumed by marine biotas such as zooplankton, phytoplankton, fishes, seabirds, cetaceans, sea turtles, echinoderms, and invertebrates. The interaction of MPs and NPs with compounds such as heavy metals, aromatic hydrocarbons, pharmaceutical compounds, pesticides, nanoparticles, organohalogens, organotins, and plastic additives cause adverse effects and are toxic to aquatic organisms. It is necessary to reduce the MPs and NPs pollution from wastewater treatment plants by using renewable or biodegradable materials and removing plastic waste from various sources.